I. Field of the Invention
This invention relates generally to biomedical apparatus for use in sleep pattern analysis, and more particularly to a vibration transducer for producing an electrical output signal relating to snoring activity of a sleeping patient.
II. Discussion of the Prior Art
In the Stasz U.S. Pat. No. 5,311,875, there is described a sensing transducer utilizing both the piezoelectric and pyoelectric properties of polyvinylidene fluoride (PVDF) film material which, when appropriately mounted on a sleeping patient""s upper lip, will produce a composite output signal relating to temperature changes due to the impingement of respiratory air on the sensor and mechanical vibration due to snoring. The two signals, being of significantly different frequencies, can easily be isolated using electrical filtering techniques.
While the sensor device described in the aforereferenced Stasz patent, the content of which is incorporated by reference herein, works well with many patients, but cannot effectively be used by adult males who happen to have a moustache. Placing the sensor of the Stasz patent on a moustache serves to greatly dampen vibrational energy occasioned by snoring from reaching the PVDF film transducer. Accordingly, a need exists for an improved vibration sensing transducer apparatus that can be used with mustached patients.
The transducer of the present invention comprises a planar layer of PVDF film material having first and second major surfaces, each having a pattern of metallization thereon. A first electrically conductive lead is attached at a first terminal to the pattern of metallization on the first major surface while a second electrically conductive lead is attached at a second terminal to the pattern of metallization on the second major surface. A fabric layer is adhesively bonded to the planar layer of PVDF material in covering relation to the pattern of metallization on the first major surface and the first terminal. A thin plastic film layer is adhesively adhered to the layer of PVDF material in covering relation to the pattern of metallization on the second major surface and the second terminal. The thin plastic film layer includes an adhesive coating on an undersurface thereof allowing the transducer to be adhesively affixed to the skin of the patient. Specifically, and in accordance with a method described, the transducer is adapted to be affixed to the skin on the neck of a patient for developing an electrical signal proportional to a snoring level of a sleeping patient.